MEMORY ENHANCING ACTIVITY OF POLYHERBAL ... of administration of Medhya Rasayana on scopolamine induced memory deficits in the morris water maze and pole climbing model were evaluated

IJRPC 2016, 6(3), 556-567 Sanjay Kumar et al. ISSN: 22312781

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INTERNATIONAL JOURNAL OF RESEARCH IN PHARMACY AND CHEMISTRY

Available online at www.ijrpc.com

MEMORY ENHANCING ACTIVITY OF POLYHERBAL

FORMULATION MEDHYA RASAYANA IN SCOPOLAMINE

INDUCED AMNESIA IN RAT

Sanjay Kumar* and Minshu Prashant

Department of Pharmacology, Hygia Institute of Pharmaceutical Education and Research, Lucknow, India.

INTRODUCTION In today’s life of stress and strain, there is a dire need for agents having neuroprotective and neurophamacological activity enhancing learning and memory function of the brain. Importantly stress is also known to interfere with cognitive functions, tending to retard the memory rather than the acquisition of learning (Thakur et al 2005). Formation of memory is the most complex process and involves multiple neuronal pathways and

neurotransmitters. It is well known that the cholinergic neuronal system plays an important role in learning and memory in humans as well as animals (Kulkarni et al 2010). Based on experimental and clinical evidences, Acetylcholine is considered as the most important neurotransmitter involved in the regulation of cognitive functions. Besides the neuro pathological hallmark of the Alzheimer’s disease, neurofibrillary tangles and neuritic plaques, Alzheimer disease is

Research Article

ABSTRACT Objective: Memory enhancing activity of polyherbal formulation Medhya Rasayana in scopolamine induced amnesia in rats using morris water maze and pole climbing models. Material and Methods: About 48 male rats (200-300gm) were randomly divided into six groups and each group contains four rats. the six groups are: Control group, Diseased group (scopolamine 0.7 mg/kg i.p. treated group), Positive group (piracetam 200mg/kg p.o. treated group), Scopolamine plus piracetam group (Scopolamine 0.7 mg/kg i.p. plus piracetam 200 mg/kg p.o. group), Test dose 1 group (scopolamine plus Medhya Rasayana 100 mg/kg treated group), Test dose 2 group (scopolamine plus piracetam 200 mg/kg treated group 200 mg/kg). Results: The result of the effect of administration of Medhya Rasayana on scopolamine induced memory deficits in the morris water maze and pole climbing model were evaluated in rats. The effect of control treated, scopolamine treated (0.7 mg/kg i.p.), piracetam (200 mg/kg p.o.) and Medhya Rasayana at doses 100 mg/kg p.o. and 200 mg/kg p.o. body weight, were evaluated at regular 5 days of treatment. The transfer latency on the acquisition as well as on the retention days was found increased at 123±2.8099 sec on 5th day. The latency time of control group is 39.25±2.8099 sec on 1st day and 32±2.1602 sec on 5th day. The effect of Medhya Rasayana after continuously 5 days administration was observed and compared with scopolamine treated group and piracetam treated groups. The decrease in latency period in compared to scopolamine treated group was observed at dose of 200 mg/kg as compare to 100 mg/kg dose of Medhya Rasayana. Conclusion: Our data suggested that Medhya Rasayana of 200 mg/kg shows better result in comparison to Medhya Rasayana 100 mg/kg. Keywords: Medhya Rasayana, scopolamine, piracetam, morris water maze, pole climbing model.

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characterized by a consistent deficit in cholinergic neurotransmission particularly in basal forebrain. The therapeutic strategies to combat miseries of cognitive disorder have been aimed to improve acetylcholine activity. Therefore, the cholinergic receptors agonists (muscarinic and nicotinic) and enhancers of endogenous level of acetylcholine (synthesis promoters and inhibitors of its metabolizing enzymes) have been tried to treat senile dementia of Alzheimer’s type. Cholinesterase inhibitors are the only class of compounds consistently proven to be efficacious in treating the cognitive and functional symptoms of Alzheimer’s disease. Blockade of central muscarinic acetylcholine receptors disrupts learning and memory functions in animals as well as human beings. Anti- cholinergic drugs (muscarinic blockers) such as scopolamine have been in use as potent amnesic agents. Scopolamine induced cognitive deficit in young volunteers is similar to that occurring in senile, demented subjects when tested on same clinical battery. These studies highlight the importance of administration of drug in relation to stages of memory process. There are three basic activities associated with memory process – acquisition, consolidation and recall (Rahul et al 2009). The decrease in neurotransmitter formation and increased oxidative stress that comes with aging effect brain functions such as memory, especially recognition, and causes dementia. Acetylcholine is the first substance to be proven to be neurotransmitter and has an important role in the enhancement of sensory perception when we wake up and in sustaining attention. Acetyl cholinesterase is an enzyme that degrades the neurotransmitter acetylcholine, producing acetate and choline group. An overall decrease of acetyl cholinesterase in the brain of people with Alzheimer’s disease has been observed. Thus, natural anti dementia material that can alter the disease progression, has been of great interest to people (Kim et al 2010). Recent studies indicate that nitric oxide modulates synaptic transmission in both central and peripheral nervous system by acting as a retro gate messenger. Further, we also examined the role of nitric oxide in the ameliorative effects of Neurosteroids on the aging induced cognitive dysfunction in aged rats (Reddy et al 1998). Effect of stress on hippocampal cholinergic system varies with the strain of rat. Inconsistent and varied changes have been reported in the level of brain acetylcholine, uptake of choline, receptor activity, activity of choline acetyl transferase and acetyl cholinesterase, following stress. Central

cholinergic system particularly in hippocampus plays an undisputed key role in regulation of learning and memory, which are the key constituent of cognitive behavior. Acetyl cholinesterase enzyme enjoys a unique status, as its inhibition is the most important therapeutic means to achieve cognitive improvement in the patients of dementia at present. Outcome of certain behavioral responses depends upon the type of stress applied (Dasi et al 2005). The administration of neurotropic factors can prevent neuronal cell death during degeneration and enhanced repair mechanism after the damage (Turner et al 1996). The hippocampal formation is a key cortical structure involved in a number of normal physiological processes, including learning and memory. Glutamate is the primary excitatory neurotransmitter in the hippocampus and glutamate receptors have been implicated in the formation and retrieval of memory. Previously, we reported that cyclothiazide acts at the positive allosteric modulatory site on AMPA receptors to selectively potentiate AMPA induced release of [

3H] nor epinephrine from rat hippocampal

slices. This effect of cyclothiazide is likely mediated by inhibition of AMPA receptor desensitization (Desai M.P. et al 1995). The mosy fiber-CA3 pyramidal system which is one of the 3 major synapsis in the hippocampal formation plays a role in learning. For example, lesions in the CA3 region have been reported to impair special memory acquisition Ishihara Kumatoshi et al 1997). The Indian system of medicine is replete with medicinal plants claimed to promote learning, memory and intelligence. The plants like Acorus calamus, Bacopa monniera, Tinospora cordifolia and Withania somnifera have been investigated for their effect on cognitive function of the brain. These plants have been grouped under the general class of Medhya rasayanas that is substance/agents that counter the degenerative changes associated with aging and are beneficial in promoting intellect (Sharma et al 1981). Ayurvedic System of Medicine has mentioned several naturally occurring medicinal preparations under the category 'Medhya'. By virtue of inducing mental upliftment as major influence several medicinal plants mentioned as 'Rasayana drugs' in Ayurveda are primarily claimed as 'Medhya'. Further there is a special class of some Rasayana drugs called 'Medhya Rasayana' which is supposed to be having specific influence on higher brain functions. Medhya Rasayana is a group of medicinal plants described in Ayurveda (Indian system of medicine) with multi-fold benefits, specifically


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to improve memory and intellect by Prabhava (specific action). Medha means intellect and/or retention and Rasayana means therapeutic procedure or preparation that on regular practice will boost nourishment, health, memory, intellect, immunity and hence longevity. Medhya Rasayana is a group of 4 medicinal plants that can be used singly or in combinations. They are Mandukaparni (Centella asiatica Linn.), Yastimadhu (Glycirrhiza glabra ), Guduchi (Tinosporacordifolia and Shankhapushpi (Convolvulus pleuricaulis ), specially mentioned with wide range of applications on different systems. Yet in practice few more handful drugs used with same aim are mentioned elsewhere in the Ayurveda classical textbooks. They are Aindri (Bacopa monniera), Jyothishmati (Celastrus panniculata), Kushmanda (Benincasa hispida), Vacha (Acorus calamus) and Jatamamsi (Nardostachys jatamamsi). Medhya Rasayana is used either in polyherbal preparations or alone. This paper is an attempt to present update on these drugs. Evidences used are mostly facts from researches on animal model or on bioactive principles with some of preclinical works on human system METHODOLOGY Collection of Medhya Rasayana The sample of Medhya Rasayana were collected from local market. Animals The Nootropic activity was carried out on Wistar albino rats of either sex (180-220 g), were purchased from animal house of Central Drug Research Institute, Lucknow. They were maintained in 24 h light/dark cycle at 25±2

oC.

They were allowed to standard pellet diet and water, ad libitum. The study was approved by Institutional Animal Ethics Committee (IAEC) according to the regulation of Committee for the purpose of Control and Supervision of Experimental Animal (CPCSEA) and ethical norms was strictly followed during all experimental procedure. Drugs/Chemicals Scopolamine hydrobromide (Sigma Aldrich,USA) and piracetam (Nootropil

® , UCB

India Ltd, Vapi, Gujrat) were diluted in normal saline and administered peritoneally. Volume of administration was 1ml/100gm/body weight. All the drugs were administered orally in the morning session i.e. 8 AM-9 AM on each day.

PHARMACOLOGICAL EVALUATIONS The pharmacological evaluation of nootropic activity was done by using various extroceptive behavioral models.

Morris water maze Test (Russo et al 2005) The nootropic activity of the drug in this model was assessed by its ability to use as potent nootropic agent and protect against Scopolamine induced amnesia. Animals were first weighed and then divided into six groups of 4 rats in each groups. The rats were trained on the standard Morris navigation task in a black water tank. The rats were started from 4 different, randomly chosen start positions and trained to find an invisible platform (Diameter 11 cm) that was at a fixed position in the water tank 1 cm below the surface of the water. The temperature of the water was 20-22

oC. A trial lasted until a rat

had found the platform. If a rat did not find the platform within 300 seconds it was placed on the platform for 30 seconds and then removed from the water tank. On the first to fifth day rats were given 2 trials per day on consecutive days. Before administering the Scopolamine, standard (piracetam), and test drug total 10 trials were given to rats in 5 days of training. Pole climbing method Test (Joshi et al 2006) Passive avoidance behavior based on negative reinforcement was used to examine the long term memory. The apparatus consists of a box (27cm× 27cm × 27cm) having three wall of wood and one wall of Plexiglas, featuring a grid floor (made up of 3mm stainless steel rod set 8 mm apart), with a wooden platform (10cm × 7cm × 1.7cm) in the center of grid floor. The box was illuminated with a 15 watt bulb during the experimental period. Electric shock (20 volt A.C.) was delivered to the grid floor. Training was carried out in 2 similar sessions. Each mouse was gently place on the wooden platform set in the center of the grid floor. When the mouse stepped down, placing all its paws on the grid floor, shocks were delivered for 15 second and the step down latency, which was defined as the time (in seconds) taken by the mouse to step down from the wooden platform to grid floor with all its paws on the grid floor was recorded. Animals showing step down latency in range of 2 to 15 seconds during the first test were used for the second session and the retention test. The second session was carried out 90 minute after the first test. During second session, if the animals stepped down before 60 seconds electric shock was delivered for 15 seconds. During the second test, animals were removed from the shock


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free zone, if they did not step down for a period of 60 seconds and was subjected to retention test. Retention was tested after 24 hours in a similar manner, except that the electric shock was not applied to the grid floor observing an upper cut off time of 300 seconds. Significant increase in step down latency period value indicates improvement in the memory. The experiment was performed in different steps-

1. Familiarization: The animal was placed on the platform, after 10 second of exploration; it is return to the home cage.

2. Learning (acquisition): An unavoidable foot shock is applied once (foot shock; 50 Hz; 1.5 mA) and the animal was allowed to jump on the pole, and then returned to the home cage.

3. Retention test: 24 hours after the learning trials the animal was again placed on the platform and the time taken by the animal to jump on the pole (latency) was measured.

The nootropic activity of the drug in this model was assessed by its ability to use as potent nootropic agent and protect against Scopolamine induced amnesia. Animals were first weighed and then divided into six groups of 4 rats in each groups. Group 1: Control Group: It represented the control group (n=4). This group received normal diet and vehicle. Group 2: Disease control Group: It represented the positive control group (n=4). This group received Scopolamine (0.7 mg/kg i.p.) from 6

th to 10

th day and latency time was

noted after 45 min. administration of Scopolamine. Group 3: Positive control Group: It represented the standard group (n=4). This group received Piracetam 200 mg/kg (p.o.) from 6

th to 10

th day and latency time was noted

after 45 min. administration of Piracetam. Group 4: Scopolamine + Piracetam Group: It represented the standard group (n=4). This group received Scopolamine (0.7 mg/kg i.p.) and piracetam (200 mg/kg p.o.) from 6

th to 10

th

day and latency time was noted after 45 min. administration of Scopolamine and Piracetam. Group 5: Test Dose 1 Group: It represented the Medhya Rasayana group (n=4). This group received Scopolamine (0.7 mg/kg i.p.) and Medhya Rasayana (100 mg/kg p.o.) from 6

th to

10th day and latency time was noted after 45

min. administration of Scopolamine and Medhya Rasayana. Group 6: Test Dose 2 Group: It represented the Medhya Rasayana group (n=4). This group received Scopolamine (0.7 mg/kg i.p.) and Medhya Rasayana (200 mg/kg p.o.) from 6

th to

10th day and latency time was noted after 45

min. administration of Scopolamine and Medhya Rasayana.

BIOCHEMICAL ESTIMATION 1. Acetyl cholinesterase estimation (Mani Vasudevan et al 2007) The pharmacological estimations was done by estimating the acetylcholine level in the brain by quantifying cholinesterase inhibition. After accessing the learning and memory paradigm in scopolamine induced amnesia, rats from each group were euthanized by cervical decapitation. The whole brain was immediately removed and chilled in ice cold phosphate buffer. After washing in ice cold phosphate buffer the brain were homogenized in 5 ml of phosphate buffer in glass Teflon homogenizer. The brain homogenate was than evaluated for enzyme activity using augistinssons method of analysis.

2. MDA Estimation (Dhir Ashish et al 2007) The method is also called as lipid peroxidation. The quantitative measurement of lipid peroxidation in brain was performed according to the method of wills. The amount of malondialdehyde (MDA) an indicator of lipid peroxidation was measured by reaction with thiobarbituric acid at 532 nm, using spectrophotometer.

3. GSH or Reduced Glutathione Estimation (Dhir Ashish et al 2007) Reduced glutathione (GSH) in brain was estimated according to method described by Ellman. A 1 mL supernatant was precipitated with 1 mL of 4% sulfosalicylic acid and cold digested at 4

oC for 1 hrs. The samples was

centrifuged at 12000g for 15 minutes at 4 o

C. To 1 mL of this supernatant, 2.7 mL of phosphate buffer (0.1 M, pH 8) and 0.2mLof 5, 5, Dithio-Bis- (2-Nitro Benzoic acid) (DTNB) were added the yellow color was developed is read immediately at 412 nm at spectrophotometer.

4. Protein estimation (Lowry et al 1951) Protein concentration as estimated by the method of Lowry’s. Different dilutions of Bovine serum albumin (BSA) solutions was prepared by mixing stock BSA solution (1 mg/ ml) and water in the test tube. The final volume in each of the test tubes was 5 ml. The


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BSA range is 0.05 to 1 mg/ ml. From these

different dilutions, 0.2 ml protein solution was

pippeted out to different test tubes and 2 ml of alkaline copper sulphate reagent was added (analytical reagent). The solutions were mixed well. This solution was incubated at room

temperature for 10 mins. Then 0.2 ml of reagent Folin solution (reagent solutions) was added to each tube and incubated for 30 min. Set the colorimeter with blank with zero and the optical density (measure the absorbance) was taken at 660 nm.

RESULTS

Table 1: Estimation of Latency Time (in second) morris water maze

Day 1 Day 2 Day 3 Day 4 Day 5

Control 39.25±2.809 39.25±2.926 35.5±1.848 34.5±2.101 32±2.160

Scopolamine 0.7 mg/kg i.p. 132.5±8.539 136.5±6.849 134±6.480 126.25±5.297 123±5.066

Piracetam 200 mg/kg p.o. 42.5±2.783 37.5±2.629 33.5±1.848*

29.25±1.493α

24±1.354#

Scopolamine + Piracetam 200 mg/kg p.o.

104.5±6.980 89.5±3.068 77±2.857α

63.25±4.534#

46.25±1.750#

Scopolamine + MR 100 mg/kg p.o.

118±4.546 113.75±5.7 102.5±3.796 87.5±3.227#

75.5±2.101#


85.5±4.272 75±3.000 62.25±4.905α

53.5±4.051#

43.75±1.750#

All Values are expressed as Mean ± S.E.M (n=4) analyzed by One Way ANOVA followed by Dunnett test) Where, *p < 0.05; α p<0.001;

#p < 0.0001.

Latency time

Control

Diseased control

Positive control

Scop + Piracetam

Test dose 1

Test dose 2

0

50

100

150

200Day 1

Day 2

Day 3

Day 4

Day 5

Lat

ency

tim

e in

sec

on

d

Fig. 1: Estimation of Latency time all Values are expressed as Mean ± S.E.M (n=4) analyzed by

One Way ANOVA followed by Dunnett test Where, *p < 0.05; αp<0.001; #p < 0.0001.

Estimation of Protein

Table 2: Effect of Medhya Rasayana on Protein in morris water maze model

GROUP PROTEIN (Moles/mg)

Control 1.183±0.005

Scopolamine 0.7 mg/kg i.p. 2.279±0.074***

Piracetam 200 mg/kg p.o. 1.36±0.033

Scopolamine 0.7 mg/kg i.p.+ Piracetam 200 mg/kg p.o. 1.935±0.049***

Scopolamine 0.7 mg/kg i.p.+ M.R. 100 mg/kg p.o. 1.541±0.141*

Scopolamine 0.7 mg/kg i.p.+ M.R. 200 mg/kg p.o. 1.355±0.078**

All Values are expressed as Mean ± S.E.M (n=4) analyzed by One Way ANOVA followed by Dunnett test Where, *p < 0.05; ** p<0.001; ***p < 0.0001.


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0.0

0.5

1.0

1.5

2.0

2.5Control

Scop 0.7 mg/kg i.p.

Pira 200 mg/kg p.o.

Scop + Pira 200 mg/kg p.o.

Scop + MR 100 mg/kg p.o.


Protein

Mo

les

/mg

pro

tein

Fig. 1: Estimation of Protein: All Values are expressed as Mean ± S.E.M (n=4) analyzed by

One Way ANOVA followed by Dunnett test Where, *p < 0.05; ** p<0.001; ***p < 0.0001.

Estimation of MDA Table 2: Effect of Medhya Rasayana on MDA

in morris water maze model GROUP MDA (nmoles/mg protein)

Control 0.248±0.015



Scopolamine 0.7 mg/kg i.p.+ Piracetam 200 mg/kg p.o. 0.353±0.016*

Scopolamine 0.7 mg/kg i.p.+ M.R. 100 mg/kg p.o. 0.438±0.011***

Scopolamine 0.7 mg/kg i.p.+ M.R. 200 mg/kg p.o. 0.417±0.002**


Estimation of MDA

0.0

0.2

0.4

0.6

0.8Control

Scop 0.7 mg/kg i.p.

Pira 200 mg/kg p.o.




nm

ole

s/m

g p

rote

in

Fig. 2: Estimation of MDA: All Values are expressed as Mean ± S.E.M (n=4) analyzed by One

Way ANOVA followed by Dunnett test Where, *p < 0.05; ** p<0.001; ***p < 0.0001.


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Estimation of GSH Table 3: Effect of Medhya Rasayana on GSH in morris water maze

GROUP GSH (nmoles/mg protein)

Control 0.539±0.017



Scopolamine 0.7 mg/kg i.p.+ Piracetam 200 mg/kg p.o. 0.441±0.004



All Values are expressed as Mean + S.E.M (n=4) analyzed by One Way ANOVA followed by Dunnett test Where, *p < 0.05; ** p<0.001; ***p < 0.0001.

Estimation of GSH

0.0

0.2

0.4

0.6Control

Scop 0.7 mg/kg ip

Pira 200 mg/kg po




nm

ole

s/m

g p

rote

in

Fig. 3: Estimation of GSH: All Values are expressed as Mean ± S.E.M (n=4) analyzed by One

Way ANOVA followed by Dunnett test Where, *p < 0.05; **p<0.001; ***p < 0.0001.

Estimation of AChE Table 4: Effect of Medhya Rasayana on AChE in morris water maze

GROUP AChE (nmoles/mg protein)

Control 1.183±0.005



Scopolamine 0.7 mg/kg i.p.+ Piracetam 200 mg/kg p.o. 1.935±0.049***

Scopolamine 0.7 mg/kg i.p.+ M.R. 100 mg/kg p.o. 1.541±0.141*

Scopolamine 0.7 mg/kg i.p.+ M.R. 200 mg/kg p.o. 1.355±0.078 All Values are expressed as Mean ± S.E.M (n=4) analyzed by One Way ANOVA followed by Dunnett test Where, *p < 0.05; ** p<0.001; ***p < 0.0001.

Estimation of AchE

0.0

0.2

0.4

0.6Control

Scop 0.7 mg/kg i.p.

Pira 200 mg/kg p.o.




nm

ole

s/m

g p

rote

in

Fig. 4: Estimation of AChE: All Values are expressed as Mean ± S.E.M (n=4) analyzed by One

Way ANOVA followed by Dunnett test Where, *p < 0.05; ** p<0.001; ***p < 0.0001.


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Table 5: Effect of Medhya Rasayana in latency time (in second) in pole climbing model

Day 1 Day 2 Day 3 Day 4 Day 5

Control 55.75±9.294 52.5±10.103 52.25±10.491 48±8.205 41.25±6.574

Scopolamine 0.7 mg/kg i.p. 131.25±4.269 137.75±6.060 126.25±4.732 123.25±4.497 116.25±3.145

Piracetam 200 mg/kg p.o. 35.5±3.329 33±2.380 31.75±2.780 28.25±2.358 25.25±2.056*

Scopolamine + Piracetam 200 mg/kg p.o.

112.5±12.5 103±12.069 85±6.454 68.75±4.269*

57±5.066α


120±3.535 111.25±4.269 102.5±4.787*

97.5±5.204α

99.75±3.300*


120.75±6.101 105±4.564 93.75±6.25α

88±3.135#

82.25±2.625#

All Values are expressed as Mean ± S.E.M (n=4) analyzed by One Way ANOVA followed by Dunnett test Where, *p < 0.05; αp<0.001;

#p < 0.0001.

Latency time

Control

Diseased control

Positive contro

l

Scop + Piracetam

Test dose 1

Test dose 2

0

50

100

150

200Day 1

Day 2

Day 3

Day 4

Day 5

Late

ncy

time

in s

econ

d

Fig. 5: Estimation of Latency time all Values are expressed as Mean + S.E.M (n=4) analyzed by

One Way ANOVA followed by Dunnett test Where, *p < 0.05; αp<0.001;

#p < 0.0001.


Table 6: Effect of Medhya Rasayana on Protein in pole climbing model GROUP PROTEIN (moles/mg)

Control 1.2272±0.0989



Scopolamine 0.7 mg/kg + Piracetam 200 mg/kg p.o. 1.6632±0.1798

Scopolamine 0.7 mg/kg + M.R. 100 mg/kg p.o. 2.0452±0.1121***

Scopolamine 0.7 mg/kg + M.R. 200 mg/kg p.o. 1.815±0.0347*



0

1

2

3Control

Scop 0.7 mg/kg i.p.

Pira 200 mg/kg p.o.


Scop + M.R. 100 mg/kg p.o.


Protein

Mo

les

/mg

Fig. 6: Estimation of Protein: All Values are expressed as Mean ± S.E.M (n=4) analyzed by One Way ANOVA followed by Dunnett test Where, *p < 0.05; **p<0.001; ***p < 0.0001.


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Estimation of MDA Table 7: Effect of Medhya Rasayana on MDA in pole climbing model

GROUP MDA (nmoles/mg protein)

Control 0.243±0.008



Scopolamine 0.7 mg/kg i.p.+ Piracetam 200 mg/kg p.o. 0.324±0.009*

Scopolamine 0.7 mg/kg i.p. + M.R. 100 mg/kg p.o. 0.569±0.027***



Estimation of MDA

0.0

0.2

0.4

0.6

0.8Control

Scop 0.7 mg/kg i.p.

Pira 200 mg/kg p.o.




nm

ole

s/m

g p

rote

in

Fig. 7: Estimation of MDA: All Values are expressed as Mean ± S.E.M (n=4) analyzed

by One Way ANOVA followed by Dunnett test Where, *p < 0.05; **p<0.001; ***p < 0.0001.

Estimation of GSH Table 8: Effect of Medhya Rasayana on GSH in pole climbing model

GROUP GSH (nmoles/mg protein)

Control 0.529±0.013



Scopolamine 0.7 mg/kg i.p. + Piracetam 200 mg/kg p.o. 0.537±0.022

Scopolamine 0.7 mg/kg i.p. + M.R. 100 mg/kg p.o. 0.330±0.022***

Scopolamine 0.7 mg/kg i.p. + M.R. 200 mg/kg p.o. 0.410±0.005** All Values are expressed as Mean ± S.E.M (n=4) analyzed by One Way ANOVA followed by Dunnett test Where, *p < 0.05; ** p<0.001; ***p < 0.0001.

Estimation of GSH

0.0

0.2

0.4

0.6

0.8Control

Scop 0.7 mg/kg i.p.

Pira 200 mg/kg p.o.




nm

ole

s/m

g p

rote

in

Fig. 8: Estimation of GSH: All Values are expressed as Mean ± S.E.M (n=4) analyzed



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Estimation of AChE Table 9: Effect of Medhya Rasayana on AChE in pole climbing model

GROUP AChE (nmoles/mg protein)

Control 0.185±0.020



Scopolamine 0.7 mg/kg i.p.+ Piracetam 200 mg/kg p.o. 0.383±0.016


Scopolamine 0.7 mg/kg i.p.+ M.R. 200 mg/kg p.o. 0.285±0.009* All Values are expressed as Mean ± S.E.M (n=4) analyzed by One Way ANOVA followed by Dunnett test Where, *p < 0.05; ** p<0.001; ***p < 0.0001.

Estimation of AchE

0.0

0.2

0.4

0.6Control

Scop 0.7 mg/kg i.p.

Pira 200 mg/kg p.o.




nm

ole

s/m

g p

rote

in

Fig. 9: Estimation of AChE: All Values are expressed as Mean ± S.E.M (n=4) analyzed


DISCUSSION Memory enhancing drugs are thought to work by increasing the brain’s supply of neurochemicals (neurotransmitters, enzymes and hormones), improving brain’s oxygen supply or by stimulating nerve growth. Nootropics agents such as piracetam, aniracetam and choline esterase inhibitors like donepezil are being used for improving memory, mood and behavior but not used generally because of more side effects associated with these agents have made their applicability limited. In the present study, we have focused upon exploring the potential of Ayurvedic poly-herbal formulation, Medhya Rasayana for its efficacy in reversing the memory deficits, improving acquisition and memory retention in experimental animals using passive avoidance and morris water maze model. In the present study, Medhya Rasayana administered orally improved learning and memory of rats significantly in both models. Furthermore, pre-treatment with Medhya Rasayana (100, 200 mg/kg) protected the animals from learning and memory impairment produced by scopolamine. These findings suggested the possible neuroprotective role for Medhya Rasayana.

The scopolamine (0.7 mg/kg i.p) is a muscarinic receptor antagonist act by prolonging transfer latency. Medhya Rasayana (100, 200 mg/kg, p.o.) have reversed amnesia induced by scopolamine indicating nootropic activity which is statistically significant as compare to standard. The polyherbal formulation Medhya Rasayana and piracetam when given along with scopolamine, significantly reversed scopolamine-induced amnesia, protective effect was observed with all parameters tested at a dose of 100 and 200 mg/kg, p.o of Medhya Rasayana. In morris water maze acquisition (learning) can be considered as transfer latency on first day trials and the retention/ consolidation (memory) is examined 24 h later. The animal shows significant decrease in transfer latency as compared with the standard group. The dose of 200 mg/kg p.o of Medhya Rasayana shows significantly better response in comparison to 100 mg/kg p.o dose of Medhya Rasayana. All data’s are analyzed by one way ANOVA followed by Dunnett test to compare all groups with control group using Graph Pad Prism 5 software. The passive avoidance is a classical model for the assessment of cognitive performance after


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brain lesions or pharmacological manipulation. In this the avoidance cage consists of single box without any compartment that prevent inter compartment transfers. A sequence of stimuli is presented during which the animal has the freedom to transfer in the same compartment. Failure to transfer or the latency to transfer to a shock free area indicates the passive behavior which is used as short term memory task. Morris water maze is employed to test spatial memory, which is affected in Alzheimer’s disease. Acetylcholine is considered as the most important neurotransmitter involved in the regulation of cognitive functions. According to the cholinergic hypothesis, memory impairments in patients with senile dementia are due to the selective and irreversible deficiency in the cholinergic functions in the brain. The cognitive dysfunction has been shown to be associated with impaired cholinergic function. The selective loss of cholinergic neurons and decrease in cholinacetyltransferase activity was reported to be a characteristics of the Alzheimer disease. In the present study, MDA, GSH, and Acetylcholinesterase activity were estimated on the 5

th day. Scopolamine treatment showed

an increase in MDA and acetylcholinesterase activity and a decrease in GSH level increased the generation of free radicals. The treatment of Medhya Rasayana in rats produced a significant fall in MDA levels in comparison to that of diseased control rat. There was a significant increase in the level of GSH in the brain. REFERENCES

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MEMORY ENHANCING ACTIVITY OF POLYHERBAL ... of administration of Medhya Rasayana on scopolamine induced memory deficits in the morris water maze and pole climbing model were evaluated